1. Field of the Invention
The present invention is in the field of heating apparatus for human comfort and pertains more particularly to methods and apparatus for heating in the vicinity of a patio umbrella and host dining or patio table.
2. Discussion of the State of the Art
There are a wide variety of outdoor heating apparatus that are available for space heating in outdoor or otherwise un-heated settings. A typical fuel-burning radiant heater may be placed in an outdoor dining area, for example to provide radiant heat for patrons sitting within the influence sphere of the heater. Some businesses such as restaurants with an outdoor patio area have provided such heaters placed strategically throughout the patio dining area to provide such heating of the area.
A typical radiant heater currently available burns natural gas or propane. The heater operates at temperatures at which infrared radiant heat is produced. An annular or quasi-annular shield-type reflector redirects a small portion of the heat downward. Most of the heat travels outward heating objects in its path but not the air. A typical unit is tall, approximately 8 feet in height. The combustion chamber of the heater is supported by a hollow pillar with the reflector mentioned above located just above the heater to re-direct a small portion of the heat. Such heaters are large and cumbersome and may present as obstacles for patrons when placed in numbers to heat a general area, and can conflict with umbrellas in the same area.
The inventor is aware of a radiant heater integrated with a mechanically-operated patio umbrella that may be used in an outdoor dining area to eliminate the conflict, clutter and safety issues created by the use of separate heaters and umbrellas. This is U.S. Pat. No. 5,964,233 issued Oct. 12, 1999 to the present inventor and a joint inventor, now deceased. The estate of the deceased inventor has assigned all rights to the present inventor, and the assignment has been recorded.
In this prior apparatus the heater and chimney apparatus is integrated into the pole apparatus of the umbrella, the heater and a reflector mounted below the canopy support apparatus. The reflector redirects the heat downward and outward. Products of combustion are drawn up the chimney, forming a rising, concentrated column of hot gases. These gases eventually mix with the ambient air and are cooled to temperatures that can safely be in contact with combustible materials. A major drawback of this configuration is that the distance the gas must travel before cooling to a safe temperature is several times greater than for an unmodified patio heater. This is a major safety issue relating to building projections, trees and other overhanging objects. FIG. 3 of this prior-art patent is particularly indicative of the details of the apparatus that are improved upon by the present invention.
While the heated umbrella better utilizes available patio space than does a large cumbersome floor heater, there are several additional problems with current heated umbrellas. The center is open at the top and may allow rain to get into the controls and heater valve. Also, the center opening can allow leaves and other debris to clog the opening impeding the evacuation of combustion gases, and create a fire hazard from the ignition of trapped debris. Moreover, umbrella parts and fabric proximal to the upper edge of the canopy are exposed directly to heat, leading to overheating in those areas, often to beyond an acceptable level. These and still other problems ultimately affect safe operation of the umbrella heater of the prior art.
Therefore, what is clearly needed is an umbrella heating unit that solves the issues described above.